Question: Which is the group that caused the Congress of Vienna?
Paraphrase: Which group made the Congress of Vienna?
SPARQL (Wikidata):  select distinct ?sbj where { ?sbj wdt:P828 wd:Q46362 . ?sbj wdt:P31 wd:Q16887380 } 
Answer: Border Kingdom of Saxony-Kingdom of Prussia 1815, borderstones Belgium-Prussia